Is synthetic fluids worth it on Hondas? Always used Castrol GTX regular oil and regular Fram filters on my other Hondas. But $30 in oil and filter seems kinda high for one oil change but is it worth it in the long run? I just purchased this Civic with 115k and was wondering if it'll be ok to run it? Or worth it? Anyone run Synthetic and do you notice a better running vehicle?